Herbicidal aliphatic oxaalkyl-2,4,5-trihalogeno-imidazoles

ABSTRACT

2,4,5,-TRIHALOGENO-IMIDAZOLES SUBSTITUTED IN 1-POSITION AT THE INIDAZOL NUCLEUS BY A GROUP OF THE FORMULA R-O-A WHEREIN R REPRESENTS AN OPTIONALLY SUBSTITUTED ALIPHATIC HYDROCATBON RADICAL AND A REPRESENTS AN ALKYLENE GROUP ARE DESCRIBED, WHICH IMIDAZOLES ARE HERBICADIALLY ACTIVE AND USEFUL IN THE CONTROL OF WEEDS AND THE LIKE UNDESIRABLE PLANT GROWTH; HERICIDAL COMPOSITIONS CONTAINING SUCH INIDAZOLES AS ACTIVE INGREDIENTS AND METHOD OF CONTROLLING UNDESIRABLE PLANT GROWTH WITH THE AID OF SUCH COMPOUDS AE ALSO DISCLOSED.

United States Patent 3,813,235 HERBICIDAL ALIPHATIC 0XAALKYL-2,4,5-'I'RIHALOGENO-IMIDAZOLES Hans Rutz, Basel, and Kurt Gubler, Riehen,Switzerland, assignors to Ciba-Geigy Corporation, Ardsley, N.Y. NoDrawing. Original application Apr. 24, 1968, Ser. No. 723,903, nowPatent No. 3,625,953. Divided and this application Apr. 5, 1971, Ser.No. 131,448 Claims priority, application Switzerland, Apr. 26, 1967,5,960/67 Int. Cl. A01n 9/22 U.S. Cl. 71-92 2 Claims ABSTRACT OF THEDISCLOSURE 2,4,5,-trihalogeno-imidazoles substituted in l-position atthe imidazol nucleus by a group of the formula R-O- -A wherein Rrepresents an optionally substituted aliphatic hydrocarbon radical and Arepresents an alkylene group, are described, which imidazoles areherbicidally active and useful in the control of weeds and the likeundesirable plant growth; herbicidal compositions containing suchimidazoles as active ingredients, and method of controlling undesirableplant growth with the aid of such compounds are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION This is a division of ApplicationSer. Ser. No. 723,903,

filed Apr. 24, 1968, now U.S. Pat. No. 3,625,953.

DETAILED DISCLOSURE wherein R represents an unsubstituted or substitutedaliphatic hydrocarbon radical,

A represents an alkylene radical, and

Hal represents a halogen atom having an atomic number of at most 35.

The new imidazole derivatives of the general formula I are obtainedaccording to the invention by reacting according to procedure (a) atrihalogen imidazole of the general formula II Hal Hal HN N 91 (II) withan ether of the general formula III (III) in which formulae Hal, R and Ahave the meanings given in formula I, in the presence of an acid bindingagent; or by reacting according to the procedure (b) a trihalogenimidazole of the general formula IV Hal Hal YA-I N for with a compoundof the general formula V In the imidazole derivatives of general formulaI, R as aliphatic hydrocarbon radical can represent e.g. an alkylradical having 1 to 16 carbon atoms, preferably however, a lower alkylradical such as the methyl, ethyl, propyl, butyl or pentyl radicals,etc., also it can represent a lower alkenyl radical such as the allyl,crotyl or methallyl radical, or a lower alkinyl radical such as thepropinyl or 1-methyl-2-propinyl radical. These hydrocarbon radicals canbe monoor poly-substituted, e.g. by halogen, lower alkoxy, loweralkylthio or cyano groups. The chain of the alkylene radical A can bestraight or branched and has, preferably, 1 or 2 carbon atoms as chainmembers. Preferred halogen atoms Hal are chlorine and, particu larly,bromine.

Lower used in connection with an aliphatic radical means that the latterhas at most 4 carbon atoms.

As acid binding agents in the process according to procedures (a) and(b) of the invention, preferably inorganic bases such as hydroxides andoxides of alkali and alkaline earth metals, e.g. potassium or sodiumhydroxide, as well as alcoholates of low alkanols with alkali metalssuch as sodium and potassium methylate, ethylate, propylate,isopropylate, butylate, particularly potassium tert. butylate, ormixtures of hydroxides and alcoholates are used. It is of advantage toperform the process according to procedures (a) and (b) in the presenceof solvents or diluents which are inert to the reaction partners, i.e.:hydrocarbons, halogenated hydrocarbons, amides such as dialkylcarboxylic acid amides, ethers and ether type compounds, and alsoalcohols in the case of procedure (b).

In the process according to procedure (a) of the invention,advantageously the trihalogen imidazole of the general formula II isconverted with one of the strong inorganic bases mentioned above intothe corresponding imidazole salt. Because of its sensitivity to air,this is preferably reacted in an inert gas atmosphere, e.g. undernitrogen, with an ether of general formula III.

Of the symbols Y and Z in general formulae IV and V, one represents thehydroxyl group and the other a halogen atom, or one represents the groupO-Me wherein Me is a metal atom and the other represents a halogen atom.

0f the starting materials embraced by the general formulae II and IVsome are known and some are new. 2,4,5-trichloroimidazole falling underthe general formula II can be prepared by reacting2,4,5-tribromoimidazole with HCl. The compound falling under the generalformula IV, in which e.g. Hal in 2-position is chlorine and in 4- and5-position is bromine, and in which Y-A represents chloromethyl, can beprepared by reacting the hydroxymethyl-tribromo derivative with thionylchloride in dimethyl formamide.

Some of the new imidazole derivatives are crystalline,

.., a 3,813,235 up other's'are oils. The new 'cohipoundsare stable anddis solve well in the usual organic solvents. They are only slightlytoxic to warm blooded animals.

The new imidazole derivatives of the general formula I have very goodherbicidal properties. They are excellently suited for influencing thegrowth of plants,and especially for the control of weeds and the likeundesirable plant growth in various cultivated areas.

The imidazole derivatives of the general formula I are used incompositions in amounts of 0.5 to 10 kg. of active substances perhectare. Preferred dosages are between 1.25 and kg. of active substanceper hectare. These compositions comprise additives usual in vweedkillers such as agriculturally acceptable non aqueous or partiallyaqueous carriers and distributing agents.

Thus, the compositions according to the invention can be in the form ofand applied as solutions, dusts, sprinkling agents, particularlyhowever, in the form of solutions which can be emulsified in water orpowders which can be dispersed in water. A fine distribution of theactive substances must be attained on application.

The content of active substance in the compositions according to theinvention varies within the range of 1 and 90 parts per 100 parts byweight of the composition.

Dusts and sprinkling compositions, which latter also embrace granulates,can be produced by mixing or milling the active substance with the usualsolid carriers. Examples of such are: talcum, diatomaceous earth,kaolin, bentonite, calcium carbonate, tricalcium phosphate, sand, andalso sawdust, ground cork and other materials of vegetable origin. Thesubstance can also be brought onto carriers by means of a volatilesolvent.

Wettable powders are obtained by mixing and milling together the activesubstance with solid carriers such as chalk, kaolin, highly dispersedsilicic acid and silicates, and also with the necessary amounts ofwetting and dis-' persing agents to a particle size of 0.05 to 40microns.

Also emulsifiable solutions serve for the production of aqueousapplication forms, e.g. solutions of the active substance in higherboiling organic solvents such as xylene, to which, if desired, suitablesolubility promoters and/or suitable emulsifying agents are admixed:

In a similar way, liquid or paste-like concentrates can be produced bymixing the active substance with dis persing agents, organic solventsand, optionally, pulverized solid carriers, in suitable apparatus untilhomogeneity is attained. These concentrates are then diluted with waterbefore use.

Suitable emulsifying and dispersing agents are, e.g. anion active alkalimetal salts of sulphuric acid monoesters of long chain aliphaticalcohols, ofaliphatic-aromatic sulphonic acids or of long chainalkoxyacetic acids, and non-ionogenic emulsifying and dispersing agentsfrom the classes of polyethylene glycol ethers of fatty alcohols oralkyl phenols, higher polycondensation products of ethylene oxide, andaliphatic-aromatic polyglycol ethers, as well as mixtures thereof withanion active emulsifying agents.

All compositions according to the invention can also contain additivesto increase the stability to rain and light as required. In additionthey can also contain additives which facilitate the adhesion and, thus,the penetration into the substrate, e.g. animal, vegetable and mineraloils. They can further contain other biocidally active substances, alsofertilizers, trace elements etc. v

The following examples describe the production of the new activesubstances; following thereafter, the production of some typical formsfor application of the compositions according to the invention isdescribed. Where not otherwise expressly stated, parts are given asparts by weight and the temperatures are given-in'degrees Centigrade.Wherever mentioned, parts by weight are related to parts by volume asgrams to milliliters.

' into 15,000 parts of water. The solid product is filtered,

EXAMPLE 1 H 2 parts of sodium hydroxide in parts by volume of methanolare added to -a solution of 15.2 parts of 2,4,5-tribromoimidazole in 100parts by volume of methanol and the resultant solution is evaporated at40 under water pump vacuum. The colourless, solid residue (sodium saltof tribromo-imidazole) is slurried and concentrated in vacuo twice with100 parts by volume of anhydrous benzene each time in order to removewater adhering azeotropically. thereto.1The dry sodium salt oftribromo-imidazole is suspended in 200 parts by volume of anhydrousbenzene. A solution of 4 parts of methoxymethyl chloride in 100 parts byvolume of benzene is added dropwise to the suspension at roomtemperature while stirring and introducing nitrogen, whereupon aslightly exothermic reaction takes place and the sodium salt of thetribromo-imidazole dissolves and sodium chloride precipitates. Themixture is then stirred, first for 1 hour at room temperature, then for1.5 hours at 60. After cooling,'the reaction mixture is extracted withwater 'and then with 2N sodium carbonate solution to remove sideproducts. On acidifying the alkaline aqueous phase with concentratedhydrochloric acid, unreacted tribromo-imidazole precipitates as acolourless precipitate. After drying over sodium sulphate, the benzenephase is concentrated in vacuo. The oily residue,1-methoxymethyl-2,4,5-tribromo-imidazole, crystallises and afterrecrystallisation from ether/petroleum ether, melts at 92-94.

EXAMPLE 2 (a) 1058 parts of hydrogen chloride are introduced into astirred solution of 890 parts of 2,4,5-tribromo-imidazole in 2800 partsby volume of dimethyl formamide, the temperature being allowed to riseto 110 during the introduction. The reaction mixture is kept at 130 for6 hours. On cooling to room temperature the solution solidifies, and theresulting slurry of crystals is charged washed with water and dried.Recrystallization from 50% aqueous alcohol yields2,4,5-trichloro-imidazole melting at 177 180 with decomposition.

(b) A solution of 4 parts of sodium hydroxide in 100 parts-by volume ofmethanol is added to a solution of 17.1 parts of2,4,5ftrichloro-imidazole in'IOO parts by volume of methanoland theresulting solution is evaporated at 40 under water pump vacuum. Thesolid residue is slurriedtwice with 100 parts by volume of anhydrousbenzene and'the solvent evaporated in vacuo in order to remove any wateradhering thereto. The dry sodium salt of trichloro-imidazole issuspended in 300 parts by volume of anhydrous benzene. A solution of 8parts of methoxymethyl chloride in.100 parts by volume of ben- 5 zene isadded dropwise to the suspension at room temperature while stirring andintroducing nitrogen, whereupon a slightly exothermic reaction takesplace and the sodium salt of the trichloro-imidazole dissolves andsodium chloride precipitates. The mixture is then stirred,

first for 1' hour at room temperature, then for 1.5 hours EXAMPLE 3 (a)180 parts of thionyl chloride are added dropwise to a stirred solutionof 426 parts of 1-hydroxymethyl-2,4,5- tribromoimidazole in 1200 partsby volume of dimethyl formamide at a temperature of 0". The reactionmixture is stirred for 3 hours at room temperature and then for 1 hourat and, after recooling to room temperature, poured into 5000 parts ofwater. The precipitated solid product is filtered, washed with water anddried. After recrystallization from benzene, 1-chloromethyl-4,5-dibromwZ-chIoro-imidazole is obtained, M.P. 86-87.

(b) A solution of 15.5 parts of1-chloromethyl-4,5-'dibromo-Z-chloro-imidazole and 6.8 parts of sodiumethylate 5 in 100 parts by volume of anhydrous alcohol is heated toreflux temperature for 12 hours. The solvent is then removed and theresidue dissolved in chloroform/ water. The chloroform phase is Washedwith water, dried over sodium sulphate and evaporated.1-ethoxymethy1-4,5-dibromo-2- chloro-imidazole is obtained in pure formfrom the oily residue by distillation; B.P. 107-108/0.005 mm. Hg.

The new 2,4,5-trihalo-imidazole derivatives of the general formula Ilisted in the following Table are obtained in the manner described inExamples 1 to 3.

10- 1-allyloxymethyl-2,4,5-tribromo-imidazole 7213 1.5834 11-1-crotyloxymethyl-2,4,5 tribromo-in1idaz0le- 12.l-methallyloxymethyl-2,4,S-tribromoimidazole. 13.lc1515?yloxymethy1-2,4,5-trlbromoazo e. 14.l-n-hexadecyloxymethyl-2,4,5-trlbtom0- tmidazole. 15.1-(2-prop1nyl)'oxymethy1-2,4,5-t1ibromoimidazo e. 16. 1-(l-methyl-z-propirliyl) -oxymethyl-2,4,5-

am e

tribromo-innd 17 1-(2-chlorciethyl) -oxymethyl-2,4,5-trlbromoimi az e.

18. 1-(2-bromoethy1)-oxymethyl-2,4,5-trlbromoimidazole.

19 1-(2,2,2-trich1o1oethyl)-oxymethyl-2,4,5-

tribromo-imidazole.

20. 1-(2-chloro-2-methylpropyD-oxymethyl- 2,4,5-tn'bromo-imidaz9le.

21 1-(2-bromo-2-methylpropyl)-oxymethy1- 2,4,5-tribromo-imidazole.

22. 1-(2-methy10xyethyl)-oxymethy1-2,4,5-

trlbromo-imidazo e.

23. 1-(2-ethyloxyethyl)-oxymethyl-2,4,5-

tribromo-imidazole.

24. 1-(2-methylthioethyl)oxymethyl-2,4,5-

trlbromo-imidazole.

25. 1- g2-c%anoethyl)-oxymethyl2,4,5-tnbromomi azo 26.l-metgylofrymethyl-j-dibromo-2-chloro- M.P. 80-81 imi azo e.

27. 1-n-propy1oxymethyl-4,5-dibromo-2ch1oro- B.P. 103106/ umdazole. 0.01mm. Hg 28.-.. 1-ethyloxymethy1-2,4,5-trichloro-imidazole.-. B.P. 81-83!0.01 mm H 29.... l-n-propyloxymethyl-2,4,5-trlchloro- B P. 88-89!imidazole. 0.0005 mm. Hg 30.... l-isopropyloxymethyl-2,4,5-trichloro- BP. 82-84/ imidazo e. 01 mm Hg 31-... 1-n-buty1oxymethyl-2,4,5-t1ichloro-B P. 90-93 imidazo e. 0 0005 mm. Hg 32. l-sec.butyloxymethyl-2,4,fi-tlichloro- B P. 81-83! imi azole. 0 0005 mm. Hg33- 145$.butyloxymethyl-2,4,5-triehlor0- i az e. 4-..- l-all lox eth l-24 5-trichloroimidazole--.- B.P. 8184/ 3 y ym y 0.001mm .Hg 35....

1-(1-methyloxyethyl) -2,4,5-tdchlor0- imidazole.

Wettable powder The following components are used to produce (a) a 10%,(b) a 20% and (c) a 40% Wettable powder:

10 parts of 1-ethyloxymethyl-2,4,S-tribromo-imidazole, 25 parts ofsodium aluminium silicate,

30 parts of Champagne chalk,

10 parts of sodium salt of lignin sulphonic acid. 2 parts of nonylphenylpolyethyleneglycol ether (5l5 ethylene oxide radicals), 2 parts of a 1:1mixture of polyvinyl alcoholzChampagne chalk, and 21 parts of kaolin;

20 parts of 1-isopropyloxymethyl-2,4,S-tribromo-imida- 10 parts ofkieselguhr,

30 parts of Champagne chalk,

4 parts of oleyl methyl tauride sodium salt,

6 parts of naphthalene sulphonic acid/phenol sulphonic acid/formaldehydecondensate [32210.5], and

30 parts of kaolin;

40 parts of 1-methyloxymethyl-4,S-dibromo-Z-chloroirnidazole,

10 parts of sodium salt of lignin sulphonic acid,

20 parts of sodium aluminium silicate,

2 parts of sodium salt of dibutyl naphthalene sulphonic acid,

2 parts of a 1:1 mixture of polyvinyl alcoholzkaolin,

11 parts of Champagne chalk, and

15 parts of kieselguhr.

The amounts of active substances mentioned are intimately mixed with theadditives in suitable mixers and milled in corresponding mills androllers. Wettable powders are obtained which can be diluted with waterto form suspensions of any concentration desired. Such suspensions aresuitable for the treatment of cultivated plants.

Granulate The following components are used to produce (a) a 2% and (b)a 5% granulate:

5 parts of the 40% Wettable powder as described above under (c),

1 part of kieselguhr,

parts of ground limestone (0.4-0.8 mm.), and

4 parts of polyethylene glycol;

5 parts of 1-allyloxymethyl-2,4,S-trichloro-imidazole, 1.5 parts ofkieselguhr, 0.5 plagts of cetyl polyglycol ether (8 ethylene oxideradica s 87 parts of ground limestone (0.4-0.8 mm.), 5 parts ofpolyethylene glycol, and 1 part of silicic acid.

The ground limestone is impregnated with the polyethylene glycol and/orthe glycol ether respectively and subsequently mixed with the 40%Wettable powder or the mixture of active substance and kieselguhr,respectively. Kieselguhr or silicic acid respectively is then added asan anticaking agent. The granulates are especially suited for thetreatment of topsoil.

Emulsion concentrate The following components are mixed together toproduce a 10% emulsion concentrate.

10 parts of 1-allyloxymethyl-2,4,S-tribromo-imidazole,

5 parts of chlorobenzene,

10 parts of cycloehxanone,

70 parts of petroleum distillate (boiling point range 15 8- 159, 96%content of aromatic hydrocarbons), and

5 parts of emulsifier consisting of a mixture of the calcium salt ofdodecylbenzene sulphonic acid and nonylphenol polyglycol ethercondensate, (e.g. Emullat P 140 HFP, Union Chimique S.A., Brussels). I

The active substance is dissolved in the petroleum distillate, and theemulsifier added to this solution. An emul- Herbicidal activityexpressed in percent.

Time Kg. A.S./ha. evaluation expressed in days after treatment 4 3 2. 52 1. 75 1. 5 1. 25

Winter grains: Height of plants at time of treatment-mean value Wheat,20 cm. hlgh- 0 0. 5 0. 5 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 Rye, em. high 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Barley, cm. high 0 0 0 0 0 0 70 0.5 0.50.5 0.5 0 0 100 0. 5 0. 5 0. 5 0 0 0 Herbicidal eflect 69 100 100 100100 100 100 Winter grains:

Wheat, 50 cm. high 0 0 0 0 0 O 0 0 0 0 0 0 Rye, 40 cm. high 0 0 0 0 0 00 0 0 0 0 0 Barley, 40 cm. high- 0 0 0 0 0 0 0 0 0 0 0 0 Herblcldalefieet 95 95 95 95 95 90 98 98 98 98 98 90 Summer grains:

Wheat, 30 cm. high l8 0. 5 0 0 0 0 0 53 0. 5 0 0 0 0 0 Rye, 30 cm. high18 0 0 0 0 0 0 53 0 0 0 0 0 0 Barley, cm. high 18 0. 5 0. 6 0 5 0.6 0 053 0 0 0 0 0 0 Herblcidal efiect 18 100 100 100 97 97 97 53 99 99 98 9898 98 10=normal growth =all plants were dead 91-=graduated increase indamage Ray Mus- Actlve substance (5 kgjha.) grass tard Millet1-ethyloxymethyl-2,4,5-tribromoimidazole 0. 5 0. 5 0l-n-propyloxymethyl-2,4,5-tribromoimidazole 2 0 01-isopropyloxymethyl-2,4,5-tribromo-imidazole 0 0 0l-n-propyloxymethy1-4,5-dibromo-2-ch1oroimi rl m nl n 4 0 1 51-methyl-2,4,5-triboromo-imidazole (known) l0 1. 5 10 II. Post-emergencefield tests. (a) Selective Tests in winter and summer grains.

(1) Active substance used (A.S.): 1-ethyloxymehyl-2,4,

S-tribromo-imidazole.

(2) Weeds normally present: Chenopodium album, Po lygonum c0nv.,Polygonum pers. and Capsella bursa past.

(b) Selective Test in summer wheat (Svenno).l-allyloxymethyl-2,4,5-tribromo-imidazole was used in an amount of 1.25kg./ha. as active substance.

At the time of application of the active substance the test plants wereca. 20 cm. high.

Evaluation of the test plants was made 7, 14 and 21 daysv afterapplication.

Weeds normally present were those given under (a) 2) above as well asSinapis arv.

Results (time of evaluation expressed in days) Test plants wheat Nodamage. N o damage N 0 damage Svenno. Herbicidal afipr-r 100 /2 100 95We claim:

1. A herbicidal composition comprisingl-allyloxymethyl-2,4,5-tribromo-imidazole and an agriculturallyacceptable non-aqueous or partially aqueous carrier.

2. A method for controlling undesirable plant growth which comprisesapplying to an area to be so controlled a.

herbicidally eifective amount of1-allyloxymethy1-2,4,S-tribromoimidazole.

References Cited UNITED STATES PATENTS 3,501,286 3/1970 Draber et al.7192 3,423,420 1/ 1969 Buchel et a1. 260309 LEWIS GOTTS, PrimaryExaminer C. L. MILLS, Assistant Examiner

